Table of Contents
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(C)
Copyright 2001 Alex Iliasov
email:alex@users.kyrnet.kg
Lemick Basic will support all standard features of object-oriented programming language. Now it supports classes as abstract object descriptions, public and private class members, overloading of methods, contructors and destructors, automated creation of contructors if none provided by the programmer, automated complementation of contructors with calls to sub-constructors - contructors of included or inhereted classes; single and multiple inheritance: child class has all the members of the parent class(es) plus his own members. In Lemick it is said that class1 extends class2. Since extended class has all members of any of his parent classes, instances of this class could be used instead of parents's in any occasions: when calling methods or passing it as an argument of a function and etc.
User types defined through TYPE ... END TYPE statements are also classes, but only one method declaration (with an exception for it overloaded instances) is allowed - init() - the constructor; all members in such classes are always public.
Example of complex number class (just a draft):
'class
implementing complex numbers
'it was boring for me to overload all functions and write all that
'stuff. anyway idea is clear
'mainly this is an example how overloading of built-in functions can be
used
'this code also uses very intricate feature of Lemick Basic - special
algorithm
'for garbage collection - look at overloaded '+' code
class
cmplx
public
dim r as double,i as double
sub init()
r=0:i=0
end sub
sub init(a as double,b as double)
r=a:i=b
end sub
function str() as string
str="("+str(r)+","+str(i)+")"
end function
function inv() as cmplx
i=-i
inv=me
end function
function operator+(aaa as cmplx) as cmplx
dim f as cmplx 'if
you have to write the same, for example in C++, then
f.r=r+aaa.r 'you
will face the problem- compiler generates call
f.i=i+aaa.i 'to
destructor (for f variable) just befor the function returns,
operator+=f 'so
return value will be currupted. Lemick doesn't, this
end function
'allows so simple implementation
of overloaded '+'
function operator+(aaa as double) as
cmplx
dim f as cmplx
f.r=r+aaa
operator+=f
end function
function operator*(aaa as cmplx) as cmplx
dim f as cmplx
f.r=r*aaa.r+i*aaa.i
f.i=r*aaa.i-i*aaa.r
operator*=f
end function
function re() as double
re=r
end function
function im() as double
im=i
end function
function len() as int
len=len(str(me))
end function
function len(k as int) as int
len=len(str(me))*k
end function
end class
dim z as
cmplx(2,2), w as cmplx(1,-6)
dim zzz(10000) as cmplx(1,1)
dim x as string
print "x=";x
print "z=",z
print "w=",w
print "w+z",w+z
print "z+w*z+5.7",z+w*z+5.7+z
print "z=",z
print "w=",w
print "Hello!"
print z.im
print z.re
print z.inv
print zzz(5)
print len(z)
print len(z,2)
